System and method for dilating and adjusting flexibility in a guiding device

ABSTRACT

This disclosure is directed to systems and methods for providing a guiding device having a dilatable, drilling tip. The tip is formed by wound helical members such that resistance to rotation in an unwinding direction dilates the tip. 
     The helical members are configured so that the dilatable tip increases in stiffness when the helical members are tensioned by a resistance to rotation in the winding direction. In some embodiments, application of relative force between coaxial inner and outer tubular members is used to control the dilation, stiffness and drilling of the guiding member.

FIELD OF THE PRESENT INVENTION

The present invention relates to a guidewire or guiding catheter, andmore particularly to such a device that is configured to cross a totallyoccluded vessel.

BACKGROUND OF THE INVENTION

Occlusive vascular disease is generally characterized by a hardened,calcified deposit blocking the flow of blood through a blood vessel.Occlusive vascular disease can cause blockages in both coronary andperipheral blood vessels. Particularly serious examples includesituations in which the lesion and deposit completely block the vessel,a condition known as chronic total occlusion (CTO). A typical CTO is alesion located in a blood vessel of a patient that results from anaccumulation of deposits, typically calcified fibrin, therein.

Traditionally, this type of disease has been treated by both bypasssurgery and/or drug therapy. Recently, it has been discovered thatocclusive vascular disease can also be treated by advancing a guidewirethrough or across the diseased location to create a passageway forinterventional treatment, i.e. angioplasty. Alternatively, guidingcatheters intended to achieve similar functionality have also beenemployed. In these procedures, the guidewire is used to puncture throughthe hard deposit in order to create a pathway for balloon catheter orstent delivery to the lesion site. Techniques in this regard can includewhat is known in the art as “dottering” by which the device is subjectedto short alternating advancing and retrograde movement so the tip or thelike that engages the lesion site imparts short thrusts to in a sensepeck away at the diseased location.

Typically, a guidewire and a catheter are separate devices that are usedin percutaneous transluminal coronary angioplasty (PTCA) procedures,with the guidewire performing essentially a guiding function for thePTCA catheter that effects the desired medical procedure. Accordingly,significant challenges exist in the design of guidewires and guidingcatheters. For example, positioning the guiding device at theappropriate location in the patient's anatomy is a difficult process,requiring the navigation of the tortuous vasculature and a successfulcrossing of the lesion while maintaining the alignment of the tip of theguiding device to prevent perforation of the vessel wall.

Further, guiding devices intended for use in CTO face additionalchallenges. Often, the true lumen of the vessel is embedded in theocclusion and is surrounded by false lumens that have been created overtime. Attempts to cross the true lumen can result in the tip of theguiding device deflecting into the false lumens of the occlusion, whichmay result in vessel perforation, dissection, or release of plaqueparticles into the bloodstream. Moreover, during crossing, the tip ofthe guiding device has a natural tendency to be directed toward the sideof the occlusion rather than the center due to the configuration of theocclusion, which can also result in vessel perforation, dissection andinability to cross the occlusion.

As a result, it is advantageous for guiding devices intended for use inCTO procedures with a number of functional features, some of which areopposed by nature, requiring a fine balance to be struck in order toachieve the desired performance. For example, the guiding device must beflexible enough to navigate through tortuous pathways within the body,consisting of bends, loops and branches. However, they also must besufficiently stiff to provide the necessary pushability to overcomefriction and occlusions as they are advanced into position. Guidingdevices must also have sufficient stiffness to serve as a conduit forother devices that are advanced over or through them. In addition,guiding devices must be torqueable to facilitate directional changes asthey are guided into position.

Therefore, a need remains for a medical device that can be easilypositioned prior to and during lesion crossing and/or treatment and alsoreduces the risk of perforating the blood vessel. It would beadvantageous to provide such a guiding device with the flexibility to beadvanced through the vasculature while remaining central to the lumen ofthe vessel. It would also be advantageous to combine the necessaryflexibility with the stiffness necessary to cross occluded lesions.Further, it would be advantageous to minimize the possibilities of thetip of guiding device deflecting off the cap of the lesion into thesubintimal space. It would also be advantageous to minimize the risk ofperforating the vessel wall due to misalignment of the tip of theguiding device. As will be detailed in the discussion follows, thisinvention satisfies these and other goals.

SUMMARY OF THE INVENTION

In accordance with the above needs and those that will be mentioned andwill become apparent below, this disclosure is directed to a guidingdevice comprising an elongated body and a dilatable tip, wherein the tipincludes a plurality of helical members having a wound configurationsuch that resistance to rotation in an unwinding direction dilates thetip and wherein the helical members form threads configured to provide adrilling action when the guiding device is rotated in a windingdirection. Preferably, the helical members are formed fromnickel-titanium alloy. The helical members are configured so that thedilatable tip increases in stiffness when the helical members aretensioned by a resistance to rotation in the winding direction.

In one embodiment, the elongated body comprises a solid guidewire.Preferably, the helical members are wound in an overlappingconfiguration in the noted embodiment. In another aspect, the distal tipcan be configured to exhibit a deflected configuration when the helicalmembers are untensioned and exhibit a substantially straightconfiguration when the helical members are tensioned.

In another embodiment, the elongated body comprises an outer tubularmember disposed coaxially over an inner tubular member, wherein aproximal end of the helical members is secured adjacent a distal end ofthe outer tubular member and wherein a distal end of the helical membersis secured adjacent a distal end of the inner tubular member.Preferably, the device also includes an elastic membrane supported bythe helical members.

In one configuration, axial movement of outer tubular member withrespect to inner tubular member causes the helical members to deflectradially so that the tip of the guiding device dilates. Preferably, thetip is configured so that application of axial force to outer tubularmember in a proximal direction relative to inner tubular memberincreases stiffness in the tip. In the noted embodiments, a knob securedto a proximal end of the outer tubular member and coaxially disposedover the inner tubular member is preferably configured to allow theapplication of rotational and axial force to outer tubular memberrelative to the inner tubular member.

In another aspect, the inner tubular member further comprises a lumenconfigured to receive an elongated device for performing anintravascular procedure.

This invention is also directed to a method of treating occlusivevascular disease of a blood vessel, including the steps of providing aguiding device comprising an elongated body and a dilatable tip, whereinthe tip includes a plurality of helical members having a woundconfiguration and wherein the helical members form threads, advancingthe guiding device through the blood vessel until the tip is adjacent anocclusive lesion, rotating the guiding device in a winding direction sothat the threads drill into the lesion, and radially displacing aportion of the lesion by rotating the guiding device in an unwindingdirection to dilate the tip. Preferably, the method also includes thestep of stiffening the tip by rotating the guiding device in the windingdirection against resistance.

One embodiment of the method involves the use of an elongated body whichfeatures an outer tubular member disposed coaxially over an innertubular member, wherein a proximal end of the helical members is securedadjacent a distal end of the outer tubular member, wherein a distal endof the helical members is secured adjacent a distal end of the innertubular member. In this embodiment, the step of radially displacing thelesion preferably comprises applying a rotation force to the outertubular member in the unwinding direction relative to the inner tubularmember or applying an axial force to the outer tubular member in adistal direction relative to the inner tubular member. Further, thisembodiment can include the step of stiffening the tip by applying arotation force to the outer tubular member in the winding directionrelative to the inner tubular member or by applying an axial force tothe outer tubular member in a proximal direction relative to the innertubular member.

Yet another aspect of the invention is directed to centering the guidingdevice in the vessel by dilating the tip. In embodiments including aninner tubular member, a further step of advancing an intravasculardevice through a lumen of the inner tubular member of the centeredguiding device can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages will become apparent from the followingand more particular description of the preferred embodiments of theinvention, as illustrated in the accompanying drawings, and in whichlike referenced characters generally refer to the same parts or elementsthroughout the views, and in which:

FIG. 1 is a simplified, partial cross-sectional view of an exemplaryembodiment of a guiding catheter having a dilatable drilling tip, inaccordance with the present invention.

FIG. 2 is a view of the embodiment shown in FIG. 1 in a dilatedconfiguration, according to the invention;

FIG. 3 is a simplified, elevational view of the dilatable tip in aretracted configuration, according to the invention;

FIG. 4 is a simplified, elevational view of the dilatable tip in adilated configuration, according to the invention;

FIG. 5 is a simplified, elevational view of the distal end of aguidewire, according to the invention;

FIG. 6 is a simplified cross-sectional view of the configuration of thedistal tip of the guidewire of FIG. 5, according to the invention;

FIG. 7 is a simplified, elevational view of the distal end of aguidewire having a deflection, according to the invention;

FIG. 8 is a schematic view of a guiding device of the invention drillingan occluding lesion, according to the invention;

FIG. 9 is a schematic view of a guiding device of the invention beingadvance into an occluding lesion, according to the invention; and

FIG. 10 is a schematic view of a guiding device of the invention,radially displacing a portion of the lesion by dilating the tip,according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

At the outset, it is to be understood that this disclosure is notlimited to particularly exemplified materials, architectures, routines,methods or structures as such may, of course, vary. Thus, although anumber of such option, similar or equivalent to those described herein,can be used in the practice of embodiments of this disclosure, thepreferred materials and methods are described herein.

It is also to be understood that the terminology used herein is for thepurpose of describing particular embodiments of this disclosure only andis not intended to be limiting.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one having ordinaryskill in the art to which the disclosure pertains.

Further, all publications, patents and patent applications cited herein,whether supra or infra, are hereby incorporated by reference in theirentirety.

Finally, as used in this specification and the appended claims, thesingular forms “a, “an” and “the” include plural referents unless thecontent clearly dictates otherwise.

The total occlusion dilatable guiding device of the present invention isdesigned to cross a totally occluded vessel. The device comprises twomeans for opening and advancing through the true lumen of the vessel. Afirst feature is that the tip of the guiding device has a threaded,drilling or boring profile, configured to cut, dislodge, displace orbreak off portions of the occlusion when rotated. Preferably, this isimplemented using a helical thread configuration. A second feature isthat the tip of the guiding device is dilatable so that the plaquedeposits forming the occlusion can be pushed away, reopening the lumen.Preferably, the distal tip has a spiral wound construction configured toexpand when an unwinding torque is applied to the tip and to retractwhen a winding torque is applied. Another feature of this constructionis that the relative flexibility of the distal tip can be changeddepending upon the amount of torque exerted. These features and otherscan be recognized more clearly with regard to the exemplary embodimentsdiscussed below.

Turning now to FIG. 1, a distal portion of guiding device 10 havingfeatures according to the invention is depicted schematically andpartially in section. Guiding device 10 comprises an outer elongatedtubular member 12 coaxially disposed over inner elongated tubular member14. A dilatable distal tip assembly 16 includes a plurality of helicalstrut members 18 extending from a proximal end 20 to a distal end 22 ofthe tip assembly 16. The distal end of outer tubular member 12 issecured to proximal end 20 while the distal end of inner tubular member14 extends coaxially through tip assembly 16 and is secured to distalend 22. Proximal end of outer tubular member 12 is joined to anactuating knob 24 which is coaxially disposed over inner tubular member14. The proximal end of inner tubular member 14 terminates in aconventional hub adapter 26, allowing access to lumen 28. As will beappreciated by one of skill in the art, lumen 28 allows introduction ofa wide variety of intravascular devices, including guidewires, dilationcathers, atherectomy catheters, stent-deploying catheters and the like.

As will be appreciated, actuating knob 24 allows outer tubular member 12to be torqued relative to inner tubular member 14. Further, sinceactuating knob 24 is slidably disposed over inner tubular member 14, anaxial force can be applied in either a distal or proximal direction atknob 24 to be transmitted to tip assembly 16. Since outer tubular member12 is secured to proximal end 20 of tip assembly 16 and inner tubularmember 14 is secured to distal end 22 of tip assembly 16, applying forcein a proximal direction to knob 24 transmits an extending force to tipassembly 16 while applying force in a distal direction transmits acompressive force. Further, application of a rotational force to knob 24transmits torque either in a winding or unwinding direction relative tohelical struts 18. Correspondingly, inner tubular member 14 attachmentto distal end 22 of tip assembly 16 acts to resist rotation of outertubular member 12, creating a winding or retracting and unwinding ordilating tension in helical struts 18 depending upon the direction ofrotational force applied to outer tubular member 12.

By applying differential forces to outer tubular member 12 and innertubular member 14, tip assembly 16 can be dilated to an expandeddiameter or can be retracted to increase its relative stiffness. Inparticular, transmitting an unwinding force or compressive force, or acombination of the two, causes the overall length of tip assembly 16 toshorten while the spiral characteristics of helical struts 18 causestheir diameter to increase.

As desired, an elastic membrane 30 can be disposed over struts 18,secured to inside of struts 18, or be supported by other suitable meansto help distribute the dilation forces to areas adjacent struts 18.Elastic membrane is preferably formed from biocompatible materials,including elastic polymers, such as silicones, polyamides, nylons, or apolyolefins such as polyethylene.

As shown in FIG. 2, tip assembly 16 dilates to an expanded configurationupon application of the pushing and/or unwinding force to knob 24.Similarly, FIGS. 3 and 4 show elevational details of tip assembly 16 inits retracted and dilated configurations, respectively. Tip assembly 16can be returned from the dilated configuration of FIG. 4 to theretracted configuration of FIG. 3 through application of force in aproximal direction or rotational winding direction, or both, to knob 24.Additionally, as discussed below, helical members 16 can have shapememory characteristics to facilitate this process. In the retractedconfiguration of FIG. 3, and with no force applied to knob 24, tipassembly 16 exhibits relatively greater flexibility as shown in FIG. 5.However, further application of extension force or winding force causesa relative increase in the stiffness of tip assembly 16 as helicalstruts 18 are tensioned and therefore provide greater resistance todeflection. In another aspect, simultaneous rotation of outer tubularmember 12 and inner tubular member 14 causes tip assembly 16 to performa drilling or boring action. Specifically, rotation of tip assembly 16in the winding direction causes helical struts 18 to function asdrilling or cutting threads.

Another dilatable guiding device embodiment of the invention is shown inFIGS. 5-7. The distal portion of dilatable guidewire 40 is shown in FIG.5. The body of guidewire 40 comprises a conventional elongated member 42that can have a solid core or can be a hypotube, depending upon thedesired characteristics. Distal tip 44 is formed from a plurality ofhelical members 46, disposed in an overlapping, spiral woundconfiguration. FIG. 6 is a cross section view of a portion of tip 44,showing adjacent helical member 46 which are slidably engaged with eachother.

Cutting thread 48 operates to keep helical member 46 aligned with eachother and provides a drilling or boring action when guidewire 40 isrotated in a winding direction with respect to the helical members 46.

Since helical members 46 can slide relative to each other, applicationof an unwinding force to distal tip 44 causes the diameter of helicalmembers to increase, dilating tip 44. As will be appreciated, theapplication of an unwinding force can include advancing the distal tip44 against a resisting obstruction, such as an occluding lesion,followed by the subsequent application of a rotating force at theproximal end of guidewire 40. When the rotating force is in an unwindingdirection relative to the configuration of helical members 46, frictionat the distal end of tip 44 from the lesion will cause helical members46 to slide relative to each other, increasing their diameter andtherefore, dilating tip 44. The overlapping configuration of helicalmembers 46 maintains a relatively uniform outer surface even whendilated, facilitating travel through the lesion. When no rotationalforce is applied to guidewire 40, the ability of helical members 46 toslide relative to each other makes tip 44 relatively flexible,particularly as compared to a solid tip. However, when a winding forceis applied, resistance experienced at the distal end of tip 44 createstension in helical member 46, increasing the stiffness of tip 44. Whensufficient rotational force is applied, the resistance caused by thelesion is overcome, resulting in the rotation of tip 44 in the windingdirection and providing drilling action due to cutting threads 48.

In some embodiments, it can be desirable to configure tip 44 so that ithas a directional deflected configuration such as shown in FIG. 7 whenno winding tension is experienced by helical members 46. One suitablemethod for implementing this feature is to differentially deform orgrind one or more of helical members 46. As will be appreciated, such aconfiguration provides guidewire 40 with improved steerability fornavigation through a patient's vasculature. When tension is applied tohelical members 46 through resistance to rotation, tip 44 assumes asubstantially straight configuration to facilitate drilling andadvancing through the occluding lesion.

In presently preferred embodiments of the invention, helical members 18and 46 are formed from a nickel-titanium alloy such as Nitinol. As knownto those of skill in the art, these alloys can exhibit shape memoryand/or superelastic characteristics. Generally, shape memory allows themember to be deformed to secondary configuration, but when heated willreturn to its original configuration. Superelastic characteristics, onthe other hand, generally allow the metal to be placed under strain anddeformed, causing a phase transformation. Once the strain is removed,the superelastic member will change phase and return to its originalshape. These phases are a martensite phase, which has a relatively lowtensile strength and which is stable at relatively low temperatures, andan austenite phase, which has a relatively high tensile strength andwhich is stable at temperatures higher than the martensite phase.

Shape memory characteristics are imparted to the alloy by heating themetal to a temperature above which the transformation from themartensite phase to the austenite phase is complete, i.e. a temperatureabove which the austenite phase is stable (the Af temperature). Theshape of the metal during this heat treatment is the shape “remembered.”The heat-treated metal is cooled to a temperature at which themartensite phase is stable, causing the austenite phase to transform tothe martensite phase. The metal in the martensite phase is thenplastically deformed, e.g. to facilitate the entry thereof into apatient's body. Subsequent heating of the deformed martensite phase to atemperature above the martensite to austenite transformation temperaturecauses the deformed martensite phase to transform to the austenite phaseand during this phase transformation the metal reverts back to itsoriginal shape if unrestrained. If restrained, the metal will remainmartensitic until the restraint is removed.

When stress is applied to a specimen of a metal, such as Nitinol,exhibiting superelastic characteristics at a temperature above which theaustenite is stable (i.e. the temperature at which the transformation ofmartensite phase to the austenite phase is complete), the specimendeforms elastically until it reaches a particular stress level where thealloy then undergoes a stress-induced phase transformation from theaustenite phase to the martensite phase. As the phase transformationproceeds, the alloy undergoes significant increases in strain but withlittle or no corresponding increases in stress. The strain increaseswhile the stress remains essentially constant until the transformationof the austenite phase to the martensite phase is complete. Thereafter,further increases in stress are necessary to cause further deformation.The martensitic metal first deforms elastically upon the application ofadditional stress and then plastically with permanent residualdeformation.

If the load on the specimen is removed before any permanent deformationhas occurred, the martensitic specimen will elastically recover andtransform back to the austenite phase. The reduction in stress firstcauses a decrease in strain. As stress reduction reaches the level atwhich the martensite phase transforms back into the austenite phase, thestress level in the specimen will remain essentially constant (butsubstantially less than the constant stress level at which the austenitetransforms to the martensite) until the transformation back to theaustenite phase is complete, i.e. there is significant recovery instrain with only negligible corresponding stress reduction. After thetransformation back to austenite is complete, further stress reductionresults in elastic strain reduction. This ability to incur significantstrain at relatively constant stress upon the application of a load andto recover from the deformation upon the removal of the load is commonlyreferred to as superelasticity or pseudoelasticity. These properties areparticularly suitable to the winding and unwinding action of helicalmembers 18 and 46 to effect the dilation and retraction of tip 16 and42.

Operation of the guiding devices of the invention is shown schematicallyin FIGS. 8-10, which feature guiding catheter 10. One of skill in theart will recognize that guidewire 40, as well as other embodiments ofthe invention, can provide similar functionality. FIG. 8 shows the tipassembly 16 of guiding catheter 10 having been advanced through apatient's vasculature to an occluding lesion 50 within the lumen ofvessel 52. At this point, tip assembly 16 is in contact with lesion 50.Simultaneous rotation of inner tubular member 14 and outer tubularmember 12 causes tip assembly 16 to drill into lesion 50. As discussedabove, application of rotational or axial forces to outer tubular member12 relative to inner tubular member 14 changes the stiffness profile oftip assembly 16, aiding the advancement of guiding catheter 10 into amicrochannel or by penetrating the calcified cap of lesion 50. As shownin FIG. 9, continued drilling rotation of guiding catheter 10 allows theformation of a channel 54 through lesion 50.

As desired, tip assembly 16 can be dilated as shown in FIG. 10. This canbe effected by applying the appropriate rotational or axial force toouter tubular member 12 relative to inner tubular member 14 as describedabove. Expansion of the tip assembly 16 applies a radial force to lesion50, pushing the plaque away to increase the diameter of channel 54 andto facilitate the further advancement of guiding catheter 10. Moreover,applying an overall unwinding rotational force to catheter 10 will alsotend to cause tip assembly 16 to dilate. Dilation of tip assembly 16tends to center guiding catheter 10 within vessel 52. This facilitatesthe process of creating channel 54 within the true lumen and can alsostabilize guiding catheter 10, such that an intravascular deviceadvanced through lumen 28 will be positioned in the correct orientationtowards the center of the lesion and will further minimize the risk ofthe intravascular device being deflected by cap of the lesion.

In operation, the use of guidewire 40 generally follows the sameprocedures. Specifically, when rotated in a winding direction,resistance from the lesion will cause an increase in tension of helicalmember 46, stiffening tip 44. Thus, by varying the amount of torqueapplied to guidewire 40, the operator can adjust the relativeflexibility of tip 44 once it is in contact with the lesion. Rotation ofguidewire 40 in the winding direction that overcomes the lesion'sresistance will cause a drilling action that can be employed to createor enlarge a channel through which to advance guidewire 40 through thelesion. Correspondingly, rotation of guidewire 40 in the unwindingdirection will create an expansion of tip 44, due to the friction of thelesion resisting the rotation of the distal end of tip 44, and thisdilation causes a radial displacement of plaque in the lesion.

As will be appreciated, chief differences between guiding catheter 10and guidewire 40 are that the guiding catheter offers relatively greatercontrol over dilation and tip stiffness through the application ofdifferential forces to outer tubular member 12 and inner tubular member14 while guidewire 40 offers a lower profile and simplified manufacture.

In general, the combination of dilation and drilling actions allow theguiding devices of the invention to cross CTO lesions while alsocreating a large enough channel to allow introduction of otherintravascular devices, such as stent delivery catheters or dilationcatheters. Since the helical members allow the stiffness of the tip tobe increased, the native flexibility in the absence of rotational oraxial tension can be greater to facilitate intraluminal steering.Correspondingly, once greater pushability is desired, tip stiffness canbe increased through application of rotational or axial tension tofacilitate crossing calcified lesions. The drilling actions of theguiding devices allow for more direct penetration of the cap of theocclusion, minimizing the tendency of the hardened cap to deflectintravascular devices being advanced into subinitimal locations.Further, dilation of the tip also helps center the device within thelumen of the patient's vessel, which also minimizes subintimal trappingand vessel perforation.

Although shown and described are what are believed to be the preferredembodiments, it is apparent that departures from specific designs andmethods described and shown will suggest themselves to those skilled inthe art and may be used without departing from the spirit and scope ofthe invention. The present invention is not restricted to the particularconstructions described and illustrated, but should be constructed tocohere with all modifications that may fall within the scope of theappended claims.

What is claimed is:
 1. A guiding device comprising an elongated body anda dilatable tip, wherein the tip includes a plurality of helical membershaving a wound configuration such that resistance to rotation in anunwinding direction dilates the tip and wherein the helical members formthreads configured to provide a drilling action when the guiding deviceis rotated in a winding direction.
 2. The guiding device of claim 1,wherein the helical members are formed from a nickel-titanium alloy. 3.The guiding device of claim 1, wherein the dilatable tip is configuredto increase in stiffness when the helical members are tensioned by aresistance to rotation in the winding direction.
 4. The guiding deviceof claim 1, wherein the elongated body comprises a solid guidewire. 5.The guiding device of claim 4, wherein the helical members are wound inan overlapping configuration.
 6. The guiding device of claim 4, whereinthe distal tip is configured to exhibit a deflected configuration whenthe helical members are untensioned and exhibit a substantially straightconfiguration when the helical members are tensioned.
 7. The guidingdevice of claim 1, wherein the elongated body comprises an outer tubularmember disposed coaxially over an inner tubular member, wherein aproximal end of the helical members is secured adjacent a distal end ofthe outer tubular member and wherein a distal end of the helical membersis secured adjacent a distal end of the inner tubular member.
 8. Theguiding device of claim 7, further comprising an elastic membranesupported by the helical members.
 9. The guiding device of claim 7,wherein axial movement of outer tubular member with respect to innertubular member causes the helical members to deflect radially so thatthe tip of the guiding device dilates.
 10. The guiding device of claim7, wherein the tip is configured so that application of axial force toouter tubular member in a proximal direction relative to inner tubularmember increases stiffness in the tip.
 11. The guiding device of claim 7further comprising a knob secured to a proximal end of the outer tubularmember, wherein the knob is coaxially disposed over the inner tubularmember and is configured to allow the application of rotational andaxial force to outer tubular member relative to the inner tubularmember.
 12. The guiding device of claim 7, wherein the inner tubularmember further comprises a lumen configured to receive an elongateddevice for performing an intravascular procedure.
 13. A method oftreating occlusive vascular disease of a blood vessel, comprising thesteps of: a) providing a guiding device comprising an elongated body anda dilatable tip, wherein the tip includes a plurality of helical membershaving a wound configuration and wherein the helical members formthreads; b) advancing the guiding device through the blood vessel untilthe tip is adjacent an occlusive lesion; c) rotating the guiding devicein a winding direction so that the threads drill into the lesion; and d)radially displacing a portion of the lesion by rotating the guidingdevice in an unwinding direction to dilate the tip.
 14. The method ofclaim 13, further comprising the step of stiffening the tip by rotatingthe guiding device in the winding direction against resistance.
 15. Themethod of claim 13, wherein the elongated body comprises an outertubular member disposed coaxially over an inner tubular member, whereina proximal end of the helical members is secured adjacent a distal endof the outer tubular member, wherein a distal end of the helical membersis secured adjacent a distal end of the inner tubular member and whereinthe step of radially displacing the lesion comprises applying a rotationforce to the outer tubular member in the unwinding direction relative tothe inner tubular member.
 16. The method of claim 13, wherein theelongated body comprises an outer tubular member disposed coaxially overan inner tubular member, wherein a proximal end of the helical membersis secured adjacent a distal end of the outer tubular member, wherein adistal end of the helical members is secured adjacent a distal end ofthe inner tubular member and wherein the step of radially displacing thelesion comprises applying an axial force to the outer tubular member ina distal direction relative to the inner tubular member.
 17. The methodof claim 13, wherein the elongated body comprises an outer tubularmember disposed coaxially over an inner tubular member, wherein aproximal end of the helical members is secured adjacent a distal end ofthe outer tubular member, wherein a distal end of the helical members issecured adjacent a distal end of the inner tubular member and furthercomprising the step of stiffening the tip by applying a rotation forceto the outer tubular member in the winding direction relative to theinner tubular member.
 18. The method of claim 13, wherein the elongatedbody comprises an outer tubular member disposed coaxially over an innertubular member, wherein a proximal end of the helical members is securedadjacent a distal end of the outer tubular member, wherein a distal endof the helical members is secured adjacent a distal end of the innertubular member and further comprising the step of stiffening the tip byapplying an axial force to the outer tubular member in a proximaldirection relative to the inner tubular member.
 19. The method of claim13, further comprising the step of centering the guiding device in thevessel by dilating the tip.
 20. The method of claim 19, furthercomprising the step of advancing an intravascular device through a lumenof the inner tubular member of the centered guiding device.